1. Field of the Invention
This invention relates to the divalent chromate ion oxidation of an allylic halide or a halomethylated aromatic to an allylic or aromatic aldehyde.
2. Description of the Prior Art
Kulka, Am. Perfumer Aromat., 69, 31 (February, 1957) and 70, 31 (November, 1957), teaches the oxidation of p-methylbenzyl chloride with aqueous sodium dichromate in the presence of sodium bicarbonate. After 20 hours of reflux, p-tolualdehyde in 90 percent yield was recovered by steam distillation. The use of a catalyst is not reported.
Cardillo et al., J.C.S. Chem. Comm., 190 (1976) and Tetrahedron Let., 44, 3985-6 (1976), teach the reaction between an alkyl, allylic or benzylic halide and potassium dichromate (K.sub.2 CrO.sub.4) in hexamethylphosphoramide (HMPA) in the presence of molar quantities of a crown ether to obtain moderate to good yields of aldehydes and ketones. Due to the general insolubility of K.sub.2 CrO.sub.4 in HMPA, Cardillo et al. supported K.sub.2 CrO.sub.4 on an insoluble polymer matrix.